As an alternative to Public Switched Telephone Network (PSTN) systems, cellular phone networks have proliferated over the last decade where users with cellular phones have access to one or more networks at almost any location. Also a recent development is the wide spread use of Voice over IP (VOIP) telephony, which uses internet protocol over wired and wireless networks. With the availability of such diverse types of communication networks and devices capable of taking advantage of various features of these networks, a new technology is bringing different communication networks together providing until now unavailable functionality such as combining various modes of communication (e.g. instant messaging, voice calls, video communications, etc.). This technology is referred to as unified communications (UC). A network of servers manages end devices capable of handling a wide range of functionality and communication while facilitating communications between the more modern unified communication network devices and other networks (e.g. PSTN, cellular, etc.).
In a system that supports multiple forms of communication, it is important for administrators to be aware of the quality of experience delivered to the users by the system. This enables the administrators to adjust the configuration of the system as needed when the quality deteriorates. Quality of experience may degrade generally due to problems in the network(s) or problems in the computing devices through which the media travels.
A user's quality of experience during an audio/video session may be measured by endpoints that generate, process, and render audio/video streams. The metrics associated with quality of experience may be calculated locally by each endpoint that participates in the session or remotely at a quality monitoring server. Individual metrics such as packet loss, audio quality degradation, dropped calls, and the like, may also be affected by each endpoint's capabilities, and measuring and/or aggregating the metrics independent of endpoints may provide only a partial picture of user's quality of experience.